Magnetic door lock system

ABSTRACT

A lock system, as for a door, has a magnetic reader which reads a magnetic code on a key moved past the reader and communicates the code to a control device having electronic logic circuits which compare the key code with a lock code. When the two codes correspond, the control device will energize an electromagnet which moves a locking armature from a catch on a locking bar, allowing the bar to be withdrawn from the door frame and the door to be opened. Provisions to give warning of unauthorized unlocking of a door, and to lock and unlock one or more doors from a central location are also provided. The magnetic system may be combined with a conventional pin-tumbler system for added flexibility or security.

United States Patent [191 Fromm Nov. 18, 1975 21 Appl. No.: 470,188

[30] Foreign Application Priority Data May 19, 1973 Germany 2325566 [52] US. Cl. 70/263; 70/264; 70/276; 70/413; 292/341.l6; 292/341.17

[51] Int. CL' EOSB 35/14; EOSB 47/04, 1505B 56/36; 13058 57/00 [58] Field of Search 70/262-264, 70/276, 277, 283, 413, 432; 292/153,

1/1974 Hochman et a1. 70/263 X 3,837,194 9/1974 Fish 70/413 X FOREIGN PATENTS OR APPLICATIONS 284,194 5/1915 Germany 292/341.16

Primary ExaminerRobert L. Wolfe Assistant Examiner-Carl F. Pietruszka Attorney, Agent, or FirmI-Ii1l, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson I 57 ABSTRACT A lock system, as for a door, has a magnetic reader which reads a magnetic code on a key moved past the reader and communicates the code to a control device having electronic logic circuits which compare the key code with a lock code. When the two codes correspond, the control device will energize an electromagnet which moves a locking armature from a catch on a locking bar, allowing the bar to be withdrawn from the door frame and the door to be opened. Provisions to give warning of unauthorized unlocking of a door, and to lock and unlock one or more doors from a central location are also provided. The magnetic system may be combined with a conventional pin-tumbler system for added flexibility or security.

3 Claims, 7 Drawing Figures U.S. Patent Nov. 18,1975 Sheet1of3 3,919,869

FIG. I

FIG. 2

Sheet 2 of 3 3,919,869

US. Patent Nov. 18, 1975 FIG. 3

FIG. 3a

25 FIG. 4

FIG. 4a

USw Patent Nov. 18, 1975 Sheet 3 of 3 MAGNETIC DOOR LOCK SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in magnetic door locks and access security systems, including surveillance and central control thereof.

2. Description of the Prior Art It is well known with mechanical pin-tumbler locks to provide master keys for all or for different portions of the locks in a security system, as for an apartment building, warehouse, or office. It is also known to lock and unlock doors by means of supplemental electromagnetic devices from a central location. In spite of the general safety and versatility of these prior devices, they have several shortcomings.

1. If a master key is unlawfully made, or such a key is lost, the security of the installation is endangered.

2. Re-establishment of security after such endangerment requires alteration of all locks and production of new sets of keys, an expensive undertaking which may also cause appreciable disruption.

3. No central locking of some or all rooms, or the surveillance of doors thereto from a central point by means of a lock-connected signal-system is possible, necessitating locking of doors one by one and provision of a separate surveillance system.

4. No immediate unlocking of all locked doors from a central location in case of danger is possible, but each door must be unlocked individually.

SUMMARY OF THE INVENTION The present invention has as its object the alleviation of the disadvantages and difficulties indicated above, particularly of increasing appreciably the security of individual locks and locking systems against unauthorized tampering and entry.

The key used in the present invention is magnetically coded. A magnetic instrument in the lock reads the keys coding when the key is brought into proximity therewith. A control device in communication with the magnetic reader in the lock compares the keys coding with a code for the door or lock and, if the codes match, unlocks the door with an electromagnet.

A signaling circuit is provided by the control device and lock to indicate when a door is locked or unlocked.

A further feature of the invention is that the control device may be connected to an alarm circuit to warn of unauthorized activation of the electromagnet to unlock a door.

The magnetic information may be encoded on the back side of a conventional-shaped key and a reading device provided on the upper side of the lock, adjacent the back of the key when it is introduced into the lock keyway.

The lock cylinder may have a radial groove in which the reading device fits to be adjacent to the back of the key.

Doors in a locking installation may be grouped to correspond with a switch plate in the control device. On the switch plate for each group of doors is disposed a switch-circuit for processing information from the keys and for actuation of the electromagnetic locking device of the doors. All the switch-circuits of each plate are connected with group switches and also with a central switch.

The locking armature of the electromagnetic locking device has an electrical contact through which the electric circuit of a signal or alarm device is closed upon a change in position of the locking armature such as in an engagement with or a disengagement from the locking bar.

Also within the scope of the invention is the use of conventional pin-cylinder locks which are modified to incorporate the magnetic protection of the present invention. An advantageous variation of an installation may be provided where only some of the locks of an installation have the additional magnetic coding, where the group and master key systems of the prior art remain in use.

These and further features of the invention will be explained on the basis of embodiments shown by way of example in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cut-away front view of a door employing the magnetic locking device of the present invention.

FIG. 2 is a top view through the door and locking mechanism-of FIG. 1.

FIG. 3 is a partial, cross-sectional detailed view through the side of the lock with a key inserted in the cylinder. FIG. 3a is a front view of the lock without the key.

FIG. 4 is a top view of the lock. FIG. 4a shows the front of the lock with the cylinder turned.

FIG. 5 shows a locking system installation with control panel and groups of doors to be secured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A locking bar 1 is slidably mounted within a door above the axis of rotation of inner and outer rotary knobs 2 and 2a, respectively, which engage via transport pins 3 and 3a in corresponding recesses 4 and 5 in the locking bar when either knob 2 or 2a is rotated. The locking bar 1 possesses catch-member 6 and 6a as well as a recess 7, into which recess may drop a locking armature 8. The locking bar 1 has an'inclination 9 making possible the engagement of a locking armature 8 with the locking bar upon full rotation of either knob. The locking bar 1 is located in a housing 10 which is installed in the door.

A housing 1 l disposed in the door frame contains the electromagnetic locking and unlocking device, which is controlled by means of a key 20 with magnetic coding which may be introduced into the lock cylinder 12. The electromagnetic device includes a lifting magnet or solenoid 13. The locking armature 8, rotatable about a pin 14, may engage the recess 7 of the locking bar.

With the aid of one of the rotary knobs, the locking bar may be brought into any of three positions:

a. Locking bar fully recessed up to the end of the housing 10. The door may be opened.

b. Locking bar moved to catch 6A. The door may be closed and opened again solely with the aid of the rotary knob.

c. Locking bar moved to catch 6. The door is bolted and the locking armature 8 has engaged the recess 7; to open the door, actuation of the solenoid 13 is necessary. Unlocking the door by rotating one of the rotary knobs alone is not possible.

The lock 12 is equipped with a reading device 21 which is connected by means of conductors 15 to an electronic control device which may be provided adjacent to the lock or at a central location. The control device may be constructed for example as a Schmitt-Trigger or as a bistable or monostable multivibrator which, upon communication with the code of a key as it is inserted into the lock, receives a starting voltage by which it activates its logic circuits. As the key is introduced further into the lock, the coding is scanned or read or interrogated by means of the reading device 21. If the code on the key matches the code recognized by the control device for that lock or door, a relay, not shown, is activated by the output device and completes a circuit via conductors 16 to energize the solenoid 13, which in turn lifts the locking armature 8 from the locking bar recess 7. The locking armature 8 has a contact plate 18, which in its raised position will close contacts 17 of a signaling or alarm device. The contacts 17 are closed when the locking armature 8 is raised and the locking bar 1 is thereby disengaged. The logic, input, and output circuitry of control devices suitable for use with this invention are well known to the art and are not shown here.

The control device input circuits may be attached constantly to a source of current, or power may be provided by means of contacts 26 provided on the lock body 12 which complete a circuit 25, 27 upon introduction of the key or upon its rotation. A circuit closure after rotation of the key will be important if the lock possesses, in addition to the reading device and electromagnetic lock, the usual mechanical tumblers. The current feed may also be provided by contacts between the door and the door frame which are closed upon the door being closed. Capacitor connections may also be used between the door and the door frame if alternating current power is used.

FIGS. 3 and 4 show a key 20 carrying a magnetic coding strip 19. The key is also formed to displace mechanical pin-tumblers of a conventional sort. The lock 12 houses corresponding pins 22 and rotary cylinder pins 23, to obtain mechanical locking capacities. Where both mechanical and. magnetic locking devices are used, the locking bar 1 may be released only when lock 12 is actuated by a key 20 which both carries the correct magnetic information and can turn the lock mechanically. A radial groove 24 is provided in the lock housing and has shoulders which limit the rotation of the lock cylinder. The magnetic key-reader device 21 is inserted into the groove 24. Conductors connect the reading device 21 with the electronic control device. From the control device, conductors 25, the contact device 26, and the conductors 27 conduct current from the control device or relay to the lifting magnet or solenoid 13. When the key is withdrawn from the lock, the control device will return to its initial state.

A lock installation in accordance with the invention affords the possibilities,

1. Of closing and opening any particular door with an individual key, a group key, or a general key, 2. Locking a group of doors from a central location, 3. Opening a group of doors from the central location, and 4. Locking the entire plant from a central location. Surveillance of individual doors and groups of doors is readily afforded by this system. Construction of an installation is shown diagramatically in FIG. 5. Groups 4 of doors T1, T2, T3, designated by Gl, Gll, and G111, are correlated with a switch-plate in the electronic control device, which stands in a central point C.

Within the control device is disposed for each door, 5 on a control panel, a functional and a switch circuit to process .information from a key in the lock and for actuating the control relay respectively. Each individual switch circuit on the control panel is connected with a group switch and with the central switch for manual locking or unlocking of each door, of all doors in a group, or of all doors in a structure, respectively.

We claim: 1. A magnetically coded prising:

a key having a pair of longitudinal surfaces, and a strip having a magnetically readable intelligenc on one of said surfaces; a lock having a rotatable cylinder into which said key may be inserted on a path, and a dynamic magnetic reading device adjacent said insertion path in said cylinder and adjacent said magnetic strip on said key; control means having input circuit means cooperating with said magnetic reading device in said lock, comparison means for comparing said intelligence on said magnetic strip of said key during insertion of said key into said lock cylinder with a control code stored in the comparison means, and output circuit means cooperating with an actuating means; said actuator means having an electro-magnet connected in said output circuit, an armature having a catch opposite a pivot bearing about which the catch may pivot toward and away from said electro-magnet in response to changes in the current flow through said electromagnet provided by said output circuit, and a door bolt movable to and from engagement with said latch, the bolt having an open position, a latched position, and a caught or locked position, said bolt being moved among its positions by a manually rotatable knob and being immobilized in its locked position by said catch on said armature. 2. A magnetically coded locking system as defined in claim 1, further comprising: said key having a mechanically-readable intelligence on the other of said longitudinal surfaces; and said lock having mechanically-displaceable lock pin means engageable with said other key surface on said path selectively to permit and prevent rotation of said lock depending on the mechanical intelligence on a key inserted thereinto. 3. A magnetically coded locking system as defined in claim 1, further comprising:

a circuit opened and closed by switch means on said armature; and remote alarm means actuated by said circuit when said circuit is opened by a change in position of said armature. 65

door locking system com- 

1. A magnetically coded door locking system comprising: a key having a pair of longitudinal surfaces, and a strip having a magnetically readable intelligence on one of said surfaces; a lock having a rotatable cylinder into which said key may be inserted on a path, and a dynamic magnetic reading device adjacent said insertion path in said cylinder and adjacent said magnetic strip on said key; control means having input circuit means cooperating with said magnetic reading device in said lock, comparison means for comparing said intelligence on said magnetic strip of said key during insertion of said key into said lock cylinder with a control code stored in the comparison means, and output circuit means cooperating with an actuating means; said actuator means having an electro-magnet connected in said output circuit, an armature having a catch opposite a pivot bearing about which the catch may pivot toward and away from said electro-magnet in response to changes in the current flow through said electro-magnet provided by said output circuit, and a door bolt movable to and from engagement with said latch, the bolt having an open position, a latched position, and a caught or locked position, said bolt being moved among its positions by a manually rotatable knob and being immobilized in its locked position by said catch on said armature.
 2. A magnetically coded locking system as defined in claim 1, further comprising: said key having a mechanically-readable intelligence on the other of said longitudinal surfaces; and said lock having mechanically-displaceable lock pin means engageable with said other key surface on said path selectively to permit and prevent rotation of said lock depending on the mechanical intelligence on a key inserted thereinto.
 3. A magnetically coded locking system as defined in claim 1, further comprising: a circuit opened and closed by switch means on said armature; and remote alarm means actuated by said circuit when said circuit is opened by a change in position of said armature. 